Independent suspension with adjustable sub-frame

ABSTRACT

A carrier housing for receiving a drive shaft that is drivingly coupled to a drive axle is provided, where the carrier housing is also connected to a sub-frame. To provide an adjustable relationship between the carrier housing and the sub-frame, the carrier housing further comprises a cover gear that may be removably coupled to a ring gear, which is attached to the sub-frame. By removing either the cover gear or the ring gear, the carrier housing may be repositioned with respect to the sub-frame.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 11/662,823 filed on May 2, 2008, which is now U.S.Pat. No. 7,850,181, which claims priority to and all the benefits ofInternational Patent Application No. PCT/US2004/031119, which was filedon Sep. 23, 2004 with the World Intellectual Property Organization, thedisclosures of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

This invention relates generally to independent suspensions, and moreparticularly, to independent suspensions having a rotatable carrier.

A common problem with motorized vehicles is that transfer of the motiveforce from the engine to the driven axle via the drive train producesvibration and noise in the vehicle. Many designs have been developed toreduce vibration and noise levels of vehicles. For example, in U.S. Pat.No. 5,185,543 to Tebbe, a tortional vibration damper is coupled to amotor vehicle drive train, which changes the natural frequency of thedrive train, making it less subject to vibration. While these designshave improved the vibration and noise levels for vehicles, a continualneed exists for novel approaches to further minimize these problems.

SUMMARY OF THE INVENTION

A carrier housing for receiving a drive shaft that is drivingly coupledto a drive axle is provided, where the carrier housing is also connectedto a sub-frame. To provide an adjustable relationship between thecarrier housing and the sub-frame, the carrier housing further comprisesa cover gear that may be removably coupled to a ring gear, which isattached to the sub-frame. By removing either the cover gear or the ringgear, the carrier housing may be re-positioned with respect to thesub-frame.

A better understanding of the objects, advantages, features, propertiesand relationships of the invention will be obtained from the followingdetailed description and accompanying drawings, which set forthillustrative embodiments that are indicative of the various ways inwhich the principles of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference may be had topreferred embodiments shown in the following drawings in which:

FIG. 1 illustrates a schematic view of a typical vehicle driveline;

FIG. 2 illustrates a perspective view of drive axle and independentsuspension assembly that uses splines to secure the carrier to asub-frame with a portion of the spring unit cut away for clarity;

FIG. 3 illustrates a rear view of an independent suspension, including arotatable carrier connected to a driveshaft and a differential unit;

FIG. 4 illustrates a top view of the independent suspension shown inFIG. 3; and

FIG. 5 illustrates an perspective view of a carrier housing associatedwith the drive axle shown in FIG. 1 with parts omitted for clarity, suchas the upper and lower control arms and the wheel assembly.

DETAILED DESCRIPTION

Turning now to the figures, wherein like reference numerals refer tolike elements, there is illustrated an independent suspension with arotatable carrier housing. FIG. 1 shows a schematic view of a typicalvehicle driveline 10 for a motorized vehicle. More particularly, thedriveline 10 includes an engine 12 coupled to a transmission 14, whichtogether provide driving input torque to a drive shaft 16 that isdrivingly coupled to a drive axle 18. Although drive axle 18 is shown asa single drive axle, drive axle 18 may also form part of a tandem driveaxle and the vehicle may also include one or more non-driving axles,such as non-drive steer axles or trailer axles. Moreover, drive axle 18may also be steerable or non-steerable. Therefore, it should beunderstood that the present invention may be used in connection withvarious different types of vehicle axles without departing from theteachings and tenets provided herein.

As shown in FIG. 2, each drive axle 18 includes a wheel end assembly 24a, 24 b on each end of the drive axle 18. It should be appreciated bythose with skill in the art, however, that dual wheels may also beincluded on each end of the drive axle to increase the load bearingcapability for the vehicle. Moreover, it is also possible for drive axle18 to be comprised of a pair of independent drive axles 18 a, 18 b,where each of the independent drive axles are associated with a wheelend assembly located on opposed sides of the vehicle.

For allowing each of the wheel end assemblies 24 a, 24 b to rotate atdifferent speeds, a differential assembly 62 may be provided. Thedifferential assembly 62 may also act to drivingly attach drive shaft 16and drive axles 18 a, 18 b. The gearing connecting drive shaft 16 todifferential assembly 62 and differential assembly 62 to drive axles 18a, 18 b is known in the industry and various differential assemblies 62may be used, such as a limited-slip differential, a No-Spin®differential, or a Torsen® differential. Differential assembly 62 ishoused within carrier housing 32 and drive axles 18 a, 18 b may also becoupled to carrier housing 32. Moreover, as shown in FIGS. 3 and 4, eachof the independent drive axles 18 a, 18 b may also be coupled to carrierhousing 32.

To support carrier housing 32, upper and lower control arms (describedin detail below) and the drive axles 18 a, 18 b associated therewith, asub-frame 60 may be attached to vehicle chassis. While it is preferredthat sub-frame 60 is attached to vehicle chassis by using a plate 34 (asshown in FIG. 2), which includes pre-drilled holes 34 a for securingsub-frame 60 to plate 34 and vehicle chassis, sub-frame 60 may alsoinclude brackets or other means for securing it to the vehicle chassis.

The sub-frame 60 is further comprised of a first side wall 62 and asecond side wall 64 with torsion bars 66 extending between the first andsecond side walls 62, 64. To further strengthen the structural integrityof sub-frame 60, an outer frame 68 may also be provided. As shown inFIG. 2, outer frame 68 may extend from the outer periphery of andperpendicularly to each of the side walls 62, 64. In addition, forfurther strengthening of sub-frame 60, support members 70 may also beprovided. In the preferred embodiment of the present invention, supportmembers 70 extend parallel to the drive axles 18 a, 18 b andperpendicularly to plate 34. Support members 70 may be formed integralwith sub-frame 60 or separately. It should be appreciated, however, thatother arrangements and designs of support members 70 may also beemployed without departing from the scope of this invention. To allowdrive axles 18 a, 18 b to be coupled to wheel assemblies 24 a, 24 b,side walls 62 and 64 may each include an aperture 62 a, 64 a. Each ofthe apertures 62 a, 64 a may also be sized to receive a cover gear 80,which may be attached to carrier housing 32 and which may be locatedwithin the apertures 62 a, 64 a.

For supporting the wheel assemblies 24 a, 24 b attached to therespective ends of drive axles 18 a, 18 b, an upper control arm 40 and alower control arm 42 are provided. Since the wheel assemblies 24 a, 24 bare mirror images of each other, only the suspension componentsconnecting wheel assembly 24 a to the drive axle 18 a will be described.As shown in FIG. 2, the lower control arm 42 may form a modifiedwishbone and has a first side 42 a and a second side 42 b. The firstside 42 a of lower control arm 42 includes a joint 46 that pivotallyattaches lower control arm 42 to support member 70, which extends fromsub-frame 60. Although joint 46 is preferably a universal joint, it mayalso be a shaft and bushing assembly, or bearings. In addition, itshould be understood that other mechanisms may also be used to pivotallyattach the first side 42 a of lower control arm 42 to support member 70.It should also be understood that there may be more than one joint 46for connecting control arm 42 to sub-frame 60 and that the lower controlarm 42 may assume varying shapes and sizes.

The second side 42 b of lower control arm 42 is pivotally attached towheel assembly 24 a. To attach the wheel assembly 24 a to the secondside 42 b of lower control arm 42, a ball joint 50 may be provided.Other means for pivotally attaching the second side 42 b of lowercontrol arm 42 may also be employed, therefore, the language describinghow lower control arm 42 is attached to wheel assembly 24 a should notbe viewed as limiting the scope of this invention.

While it is preferred that the upper control arm 40 form a single arm,upper control arm 40 may also be of a wishbone or other design. As shownin FIG. 2, upper control arm 40 has a first side 40 a and a second side40 b. The first side 40 a of upper control arm 40 is pivotally attachedto a bracket 48 by joint 51. Similar to support member 70, bracket 48may be formed as part of sub-frame 60 or exist separate andindependently therefrom. As shown in FIGS. 2 and 3, for attachment toupper control arm 40, bracket 48 is preferably positioned in the middleof side wall 62. Although joint 51 is preferably a universal joint, itshould be understood that other mechanisms may also be used to pivotallyattach the first side 40 a of upper control arm 40 to bracket 48, suchas a shaft and bushing assembly or bearings. It should also beunderstood that there may be more than one combination of brackets 48and joints 51 for connecting upper control arm 40 to sub-frame 60 andthat upper control arm 40 may assume varying shapes and sizes.

The second side 40 b of upper control arm 40 is pivotally attached towheel assembly 24 a. To attach the wheel assembly 24 a to the secondside 40 b of lower control arm 42, a ball joint 55 may be provided.Other means for pivotally attaching the second side 40 b of uppercontrol arm 40 may also be employed, therefore, the language describinghow lower control arm 40 is attached to wheel assembly 24 a should notbe viewed as limiting the scope of this invention.

For absorbing shocks and maintaining the height of the vehicle inresponse to elevational changes in the surface on which the vehiclerides, it is preferred that one spring unit 52 is provided for eachwheel assembly 24 a, 24 b. It is also possible, however, to replacespring unit 52 with a gas shock or similar means for maintaining theposition of wheel assemblies 24 a, 24 b with respect to the vehicle.Again, since the wheel assemblies 24 a, 24 b are mirror images of eachother, only the suspension components connecting wheel assembly 24 a tothe drive axle 18 a will be described. A first end 52 a of spring unit52 may be pivotally attached to bracket 53 by a joint. Although joint ispreferably a universal joint, it should be understood that othermechanisms may also be used to pivotally attach the first end 52 a ofspring unit 52 to bracket 53, such as a shaft and bushing assembly orbearings. To provide the necessary support for spring unit 52, bracket53 may be attached to vehicle chassis. It should be appreciated,however, that bracket 53 may also be attached to sub-frame 60 or plate34. It should also be appreciated that bracket 53 may also be formed aspart of the sub-frame 60 or plate 34. A second end 52 b of spring unit52 may be pivotally attached to lower control arm 42 by a joint 56.Although joint 56 is preferably a universal joint, it should beunderstood that other mechanisms may also be used to pivotally attachthe second end 52 b of spring unit 52 to lower control arm 42, such as ashaft and bushing assembly or bearings.

Since it is common for drive shafts 16 to assume different angles withrespect to the vehicle chassis, carrier housing 32 is designed to beattached to sub-frame 60 in various rotatable positions. Morespecifically, as shown in FIGS. 2 and 5, the coupling between carrierhousing 32 and sub-frame 60 allows the carrier housing 32 to be rotatedwith respect to sub-frame 60 at varying angles. Although the presentembodiment of the current invention allows for adjustments of thecarrier housing 32 with respect to the sub-frame 60 of between 2.6 and5.2 degrees, it should be understood that the degree of theseadjustments is dependent on the size of splines formed on ring gear 82and the spacing between bolts 82 a attaching ring gear 82 to side wall62, as described more fully below. Since the independent axles 18 a, 18b are mirror images of each other, only the coupling arrangement betweenthe carrier housing 32 and the first side wall 62 of sub-frame 60 forindependent axle 18 a will be described. To allow carrier housing 32 torotate with respect to sub-frame 60, carrier housing 32 includes a covergear 80 that may be located within the aperture 62 a in side wall 62 andthat is designed to form a coupling engagement with ring gear 82, asdescribed below. Moreover, the splines of cover gear 80 are designed tointerface with the splines 83 of ring gear 82 to lock the carrierhousing in place. Ring gear 82 is attached to side wall 62 of sub-frame60 and may be located proximate to aperture 62 a of side wall 62 toallow cover gear 80 to be coupled to ring gear 82. Although ring gear 82is preferably attached to side wall 62 with bolts 82 a, it should beunderstood that other attachments means may also be used and that ringgear 82 may be formed as an integral portion of the side wall 62.

To rotate carrier housing 32 with respect to sub-frame 60, cover gear 80may be unsecured from carrier housing 32 and rotated, or the ring gear82 may be unbolted from sub-frame 60 and rotated. Both of the foregoingoptions allow carrier housing 32 to be rotated with respect to sub-frame60, however, the rotation of carrier housing 32 is limited by either thespacing between bolts 82 a that attach ring gear 82 to sub-frame 60 orthe size of the splines formed on cover gear 80 and ring gear 82.

For example, when cover gear 80 is removed from carrier housing 32,carrier housing 32 may then be rotated within aperture 62 a of side wall62. Once carrier housing 32 is rotated to the desired angularrelationship (for example within 2.6 degrees) with respect to sub-frame60, cover gear 80 may be inserted within aperture 62 a and re-attachedto carrier housing 32. Because there are only a limited number of boltssecuring cover gear 80 to carrier housing 32, it should be apparent thatcarrier housing 32 may have to be rotated a few degrees in eitherdirection in order to match up bolts with the holes (not shown) in covergear 80. Once cover gear 80 is coupled to ring gear 82 and bolts aresecured to carrier housing 32, carrier housing 32 will be locked inplace and unable to rotate with respect to sub-frame 60.

By way of further example, when ring gear 82 is unbolted from sub-frame60, carrier housing 32 and cover gear 80 may be rotated within aperture62 a. Once carrier housing 32 is rotated to the desired angularrelationship (for example within 5.2 degrees) with respect to sub-frame60, ring gear 82 may be re-attached to sub-frame 60 and thereby coupledto cover gear 80. Similar to the example describing adjustment of thecover gear 80, it should be apparent that the carrier housing 32 andring gear 82 may have to be rotated a few degrees in either direction inorder to match the splines 83 and bolts 82 a with apertures (not shown)in sub-frame 60, prior to attaching ring gear 82 to sub-frame 60. Oncebolts 82 a are secured to sub-frame 60, ring gear 82 and cover gear 80will be fixedly coupled to one another carrier housing 32 will be lockedin place an unable to rotate with respect to sub-frame 60.

To reduce the speed of the vehicle or bring the vehicle to a stop, abraking system 100 may be provided. Several types of known brakingsystems may be used, including, but not limited to, dry disc brakes andwet disc brakes. Dry disc brakes for a single wheel may be furthercomprised of a disc 102 connected to an axle hub that drives thevehicle's wheel 106, two brake pads (not shown), and two pistons (notshown). One of the brake pads sit on each side of the rotating disc 102and each piston sits adjacent to one of the brake pads on the side ofthe brake pad opposite the rotating disc 102. To actuate the brake pads,a brake force may be transmitted by hydraulic fluid forcing a piston topress against a respective brake pad. The brake pad then exerts africtional force against the rotating disc 102 causing the disc 102 todecrease its rotational speed until it has stopped rotating. A wet discbrake system is comprised of similar components, but also includes afluid contained within a brake housing that surrounds that rotating discand brake pads. While the preferred embodiment of the present inventionincludes a wet or dry disc brake system, it should be evident to thosewith skill in the art that the present invention may use other brakingsystems without departing from the scope of this invention.

Although there has been no discussion of other aspects of the axleassembly, such as tie rods or sway bars it should be appreciated bythose with skill in the art that these elements are well-known in theart and that many different designs for these elements exist and arelikely to be compatible with the axle assembly described herein.

While specific embodiments of the invention have been described indetail, it will be appreciated by those skilled in the art that variousmodifications and alternatives to those details could be developed inlight of the overall teachings of the disclosure. Accordingly, theparticular arrangement disclosed is meant to be illustrative only andnot limiting as to the scope of the invention which is to be given thefull breadth of the appended claims and any equivalents thereof.

1. An adjustable carrier housing for receiving a drive shaft that isdrivingly coupled to a drive axle and attaching the drive shaft anddrive axle to a vehicle chassis, comprising: a sub-frame adapted to beconnected to the vehicle chassis with the sub-frame including aplurality of side walls each defining an aperture; a pair of cover gearshaving an outside periphery including a plurality of splines with eachof the cover gears attached to opposite sides of the carrier housing andpositioned within the apertures located on the respective side walls; aring gear positioned proximate to each of the apertures and each ringgear having an inside including a plurality of splines for cooperatingwith the splines of the cover gears; wherein the ring gears are coupledto the cover gears; and wherein the carrier housing is fixedly coupledto the sub-frame by an interlocking relationship between the splines ofthe cover gears and ring gears.
 2. The adjustable carrier housingdescribed in claim 1, wherein the ring gear is attached to the sub-frameby a plurality of bolts that are spaced apart at predetermined pointsaround each of the respective apertures.
 3. The adjustable carrierhousing described in claim 2, wherein each of the predetermined pointsare separated by an angular relationship of 5.2 degrees with respect tothe center of the aperture.
 4. The adjustable carrier housing describedin claim 1, wherein the carrier housing can be re-positioned withrespect to the sub-frame to allow the drive shaft to form a differentangle with respect to the sub-frame.
 5. The adjustable carrier housingdescribed in claim 4, wherein the carrier housing is re-positioned withrespect to the sub-frame by removing the cover gear, rotating thecarrier housing and then aligning and coupling the cover gear to thering gear and carrier housing.
 6. The adjustable carrier housingdescribed in claim 5, wherein the cover gear may be re-positioned withrespect to the sub-frame in 2.6 degree increments.
 7. The adjustablecarrier housing described in claim 4, wherein the carrier housing isre-positioned with respect to the sub-frame by removing the boltsattaching the ring gear to the sub-frame, rotating the ring gear andcarrier housing to the desired position, and re-attaching the bolts andthe ring gear to the sub-frame.
 8. The adjustable carrier housingdescribed in claim 7, wherein the ring gear may be re-positioned withrespect to the sub-frame in 5.2 degree increments.